Dandelions are one of the most common weeds of maintained turf because they can tolerate a wide variety of soils and environmental conditions. The best time to control dandelions or other broadleaf weeds is in the fall. Mid-spring is also an effective time for control, particularly when dandelions are flowering. If you wait too late in the spring, the chance of damaging off-target ornamentals, gardens and trees increases.
Although the GDD tracker http://www.gddtracker.net/ currently indicates that some areas of IN could use either esters or amines for broadleaf control, amines tend to be less volatile. Using amines could reduce the chance of off-target damage later in the spring.
In order to increase efficacy of these herbicides, do not mow directly prior to an application so that the largest leaf area is available. Also, apply the product so that it will dry on the leaf for at least 24 hours before a rain. Do not mow two to three days after application to allow the products to translocate. Finally, be sure to warn your customers to return the treated clippings to the lawn and do not use as mulch on susceptible plants for 6 to 10 weeks depending on the label of your product.
For home lawns, a good management strategy would be to limit or reduce dandelion populations by raising the mowing height and fertilizing throughout the year.